I'd recently realized that I have a hard time picturing Houston before Europeans settled here. It's hard enough for me to imagine the place before freeways. But what did it look like in 1836, when those real-estate hucksters, the Allen brothers, floated down Buffalo Bayou and founded our city?

If I wracked my brain, I could dredge up a few facts about the area before Europeans settled here. I knew the Karankawa tribe had roamed our swamps and prairies. But unconsciously, I pictured pre-urban Houston as a giant vacant lot in a Sims video game — a flat expanse of uniformly green grass just waiting to be developed.

I wondered: Had there been actual buffalo on that bayou? What did this place look like when it was wild?

Río Cíbolo

I'd called the right guy. Aulbach, a story-telling historian, gives lovely tours of Buffalo Bayou, and he'd recently been researching its name.

There were two theories about the bayou's name, he said. One was that the bayou was named not after actual buffalo - the kind with hooves - but after the buffalo fish, a flat-faced genus that looks like carp. But Aulbach doesn't subscribe to the fish theory. In part, that's because it was put forth by a Rice historian, Andrew Forest Muir, whose footnote reveals his source to have been his own grandmother.

Aulbach prefers a theory involving real buffalo. When Stephen F. Austin came to Texas to establish his Anglo colony, he used a Spanish map from about 1822, the "Mapa topografico de la provincia de Texas." Around this area, that map showed a "Río Cíbolo" - "cíbolo" being the word the Spanish explorers of the time used for bison. When Austin had the map redrawn in English, the waterway was labeled "Buffalo Bayou."

And there's plenty of archeological evidence that buffalo roamed Houston for centuries. One set of fossils, found near Armand Bayou, indicates that bison were in the area 35,000 years ago.

And in a way, they ruled the place before we got here. Ecologists call bison a "keystone species," because their enormous herds shaped prairie ecosystems. In a wet climate like Houston, their churning hooves kept trees from taking over the grasslands.

The enormous herds had once ranged from northwest Canada down to what are now the Mexican states of Durango and Nuevo León. But between the 1830s and 1880s, they were hunted nearly to extinction.

"So the bayou was named for actual buffalo?" I asked. "They were here, in Houston, in 1836?"

"Yeah," said Aulbach. "But that's the last time."

'Like a sand storm'

He pointed me to the reminiscences of Mrs. Dilue Rose Harris, who in 1836 had been an 11-year-old living near Harrisburg, then the area's largest settlement. When she was an old woman, the Texas State Historical Association published her memories of the Runaway Scrape, the bit of the Texas Revolution in which white settlers fled Santa Anna's army.

Harris wrote that in March 1836, as her family waited for news from the Alamo, "a large herd of buffaloes came by. There were three or four thousand of them. They crossed the Brazos River above Fort Bend, and came out of the bottom at Stafford's Point, making their first appearance before day.

"They passed in sight of our house, but we could see only a dark cloud of dust, which looked like a sand storm. Father tried to get a shot at one, but his horse was so fractious that it was impossible.... The buffaloes passed and went onto the coast, and the prairie looked afterwards as if it had been plowed."

That, says Aulbach, appears to be the last recorded sighting of a herd in our area. The keystone species, which had once ruled the land, disappeared here almost before anyone thought to record its passing.

The American West was busily being won, and the buffalo, like the Indians, were in white settlers' way. As the herds' numbers dwindled, their ranges contracted. By the 1870s, they were seen no farther south than the Panhandle. By the 1889, the closest herd was in Oklahoma, and it numbered a puny 25.

Only five months after Dilue Rose Harris saw that last herd, the Allen Brothers founded the city of Houston on the banks of Buffalo Bayou. But by then, the bayou's name was already all that remained of the buffalo. The animals themselves were already gone.